1. Field of the Invention
The present invention relates to a method of bonding aluminum members, and more particularly, to a method of bonding together a plurality of aluminum castings formed by die casting.
2. Description of the Prior Art
The following methods of bonding aluminum members have conventionally been available. For example, it is the recent increasing tendency for the cylinder block of a water-cooling type internal combustion engine such as an automobile engine to be manufactured from aluminum. Types of cylinder blocks include the so-called closed deck type and the open deck type. In the closed deck type cylinder block, a cooling water channel is formed around the cylinder, and members on the cylinder side and on the cylinder block side are partially bonded together at the top end. In the open deck type one, on the other hand, a cooling water channel is formed on the entire periphery of the cylinder, with the entire cylinder periphery being open at the top end of the cylinder block, and the cooling water channel is formed in the shape of glasses.
For structural reasons, the closed type cylinder block is manufactured generally by the low pressure casting method, and the open deck type is manufactured by the die casting method. Because the entire upper end of the cylinder block of the open deck type is open, this portion is low in strength. The following improvements have therefore been proposed.
For example, Japanese Unexamined Patent Publication No. 1-100352 (first document) proposes a method of fixing by welding a piece member of a prescribed shape to an opening of the cooling water channel. Japanese Unexamined Patent Publication No. 1-147145 (second document) proposes a method of fixing by welding a prescribed piece member to the open portion of the cooling water channel, in which the piece member comprises aluminum alloy having a melting point higher than that of the cylinder block body. Japanese Unexamined Patent Publication No. 2-105557 (third document) proposes a method which comprises making a prescribed plug member (piece member) from a material having a melting point lower than that of the cylinder block body, and attaching this member to the cylinder block body by heating with a heat source such as an arc or a laser.